Discuss Reduced r2 due to cladding in the Electrical Forum area at ElectriciansForums.net

Rockingit

-
Mentor
Esteemed
Arms
Supporter
Reaction score
4,133
Welcome to ElectriciansForums.net - The American Electrical Advice Forum
Head straight to the main forums to chat by click here:   American Electrical Advice Forum

Industrial refit and we’ve screwed a bunch of metal clad 13’s onto walls which are corrugated metal sheet using self tappers. Just come to do dead tests and realised that r2 is about half the value of r1 and rn - the sheet is acting a conductor. Sup Bond the sheet or not? The same walls also have 32/3 socket outlets but they’re class 2 boxes, also the board is on the same walling. Structural is bonded back at the MET. So the low down is everything has an Earth path, just in an odd way!
 

Strima

-
Esteemed
Arms
Reaction score
5,973
Only other way is to chuck all the CPCs into Wagos to isolate them from parallel paths just to check your continuity.

If you IR the sheet it would come back as needing bonding so I would just do it anyway.
 

PEG

-
Mentor
Esteemed
Arms
Reaction score
6,593
Hi bud,are these outlets on the inside or outside?
Can't imagine the sheet having to be treated different to the accessible metal clad unit,but prepared for discussion ?

....anywho...i've got me own problems...got to make an adapter to fill a 30" rubber mooring buoy with water,instead of air ?
 

telectrix

-
Mentor
Esteemed
Arms
Reaction score
65,884
Hi bud,are these outlets on the inside or outside?
Can't imagine the sheet having to be treated different to the accessible metal clad unit,but prepared for discussion ?

....anywho...i've got me own problems...got to make an adapter to fill a 30" rubber mooring buoy with water,instead of air ?
adaptors.take your pick:
Reduced r2 due to cladding 1626427197573 - EletriciansForums.net
 
OP
Rockingit

Rockingit

-
Mentor
Esteemed
Arms
Supporter
Reaction score
4,133
Strictly speaking you don't have a reduced r2. As above for initial verification you isolate the cpcs from the parallel paths to verify its integrity that is r2.
This is a true thing….. except it’s virtually impossible to isolate for testing as all the sockets are metal fixed. I’m happy I’ve continuity as I can see it all.
 

pc1966

Esteemed
Arms
Reaction score
6,812
I was going to suggest that if the CPCs go only tho the actual plate/switch you could open and check that way, as poor/missing terminal use is more likely than an open CPC half-way a long a cable.

But @westward10 beat me to it by several hours!
 

Lucien Nunes

-
Mentor
Esteemed
Arms
Reaction score
10,415
If the CPC is an insulated conductor e.g. conduit cable, then I would always test it before putting the fronts on, propping them clear of the boxes or any other metal if needed so that only the copper conductor and its connections are under test.

Much less practical is any kind of test involving a CPC via conduit / SWA / MICC which connects via the back box and hence is inseparable from the metal building structure after first fix. The chances of a secure MI gland failing to make effective contact are near zero, likewise well-erected conduit, so the likelihood of the test failing to spot a disconnect due to the parallel structure is small. In any case if the containment continuity is critical, the joints should be tested with the Ducter during erection.
 

cliffed

-
Arms
Reaction score
476
This is a true thing….. except it’s virtually impossible to isolate for testing as all the sockets are metal fixed. I’m happy I’ve continuity as I can see it all.
Agree especially if your doing an Eicr on a factory using Swa, trunking, etc R2 would be potentially lower than the R1 + R2 measured.
Thats only if you are recording that measurement by the way.
 

Reply to Reduced r2 due to cladding in the Electrical Forum area at ElectriciansForums.net

Similar Threads

Hello boys and girls. I just wondered if anyone has any tips/tricks/previous experiences about running circuits in a log cabin. I've not had to...
Replies
27
Views
1K
Hello, Just getting ready for my first scheme assessment and am completing a board change to be assessed on. Ground floor ring end to end...
Replies
14
Views
3K
  • Locked
Hi, we need some advice on our scenario with regards to our rewire plan. I will get this out of the way first... We are planning to put the house...
Replies
24
Views
2K
Hi, With Referance to the current Initial verification and periodic practical exam. Continuity of protective conductors, including main and...
Replies
3
Views
774
B
Hello fellow installers. I have just been to see a potential customer who works out of an industrial unit. Now the external of the building has...
Replies
5
Views
6K

New Posts (Please Reply)

Electrical Forum

Welcome to the Electrical Forum at ElectriciansForums.net. The friendliest electrical forum online. General electrical questions and answers can be found in the electrical forum.
Top